using System;
using System.Collections.Generic;
using System.Text;

namespace s_yuan
{
    class Program
    {
        static void Main(string[] args)
        {
            double s,s1,s2,r;
            const double PI = 3.1415;
            string x;
            Console.WriteLine("-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=");
            Console.WriteLine("-=                C#求圆,其内接,外接正方形面积(s,s1,s2)                -=");
            Console.WriteLine("-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=");
            Console.WriteLine("");
            do
            {
                Console.WriteLine("");
            Console.Write("请输入圆的半径 r=");
                r = Double.Parse(Console.ReadLine());
                s = PI * r * r;
                s1 = 2 * r * r;
                s2 = 4 * r * r;
                Console.WriteLine("");
                Console.WriteLine("圆面积:{0}", s, s1, s2);
                Console.WriteLine("圆内接正方形面积:{1}", s, s1, s2);
                Console.WriteLine("圆外接正方形面积:{2}", s, s1, s2);
                Console.WriteLine("");
            Console.Write("[Go on ?  Y/N]:");
                x = (Console.ReadLine());
            }while (x == "y");
            Console.WriteLine("End!!!");
            Console.ReadLine();

        }
    }
}